1. Field of the Invention
The present invention relates generally to optical readers, and more particularly to an optical reader that changes a light scanning direction. The optical reader of the present invention is especially suitable for barcode scanners which optically read a barcode put on merchandises in POS systems and the like.
2. Description of the Related Art
Recently, barcode scanners have become more frequently used for cashiers in supermarkets, discount stores, home centers, etc. In general, operators who use a barcode scanner fixed onto a cashier table move a merchandise on which a barcode is printed, whereby the merchandise may pass across a scanning pattern emitted in a predetermined direction from a read window of the barcode scanner.
The scanning pattern is usually fixed to one pattern, and its emitting direction is preset and fixed in accordance with the installation and usage environments of the scanner at the time of manufacturing. The xe2x80x9cinstallation environmentxe2x80x9d, as used herein, means a direction in which the read window is to be installed in a cashier table; more concretely, whether the read window is arranged parallel or perpendicular to the cashier table. The former barcode scanner is called a lateral type, and the latter a longitudinal type. The xe2x80x9cusage environmentxe2x80x9d, as used herein, means a moving path of a merchandise onto which a barcode is printed; for example, whether the merchandise is to be moved from right to left or left to right, even in the same lateral type. The usage environment depends upon each operator""s height, experience and the like. The emitting direction is usually preset and inclined by a predetermined angle relative to a direction perpendicular to the read window, toward an upper stage from which a merchandise comes (for instance, which is a right side if the merchandise moves from right to left).
With the spread of barcode scanners, prompt reading of barcodes and efficient manufacturing of the barcode scanners has been strongly demanded.
However, the conventional longitudinal and lateral barcode scanners are different in manipulation and optimal scanning-pattern emitting directions. Even in the same lateral type, a proper emitting direction is different between one which moves merchandise from right to left, and another which moves merchandises from left to right. Therefore, in an attempt to install and use the conventional barcode scanners each store has ordered apparatuses having a different pattern emitting directions which correspond to their installation and usage environments.
A change of the emitting direction requires a change of inclination of an optical system that generates a scanning pattern and/or an arrangement of optical element(s). Consequently, each barcode scanner even for the same type, should be manufactured differently in emitting direction for every business type of different installation and usage environments, causing inefficient manufacturing and price increasing. On the other hand, primarily for manufacturing purposes, there have been proposed apparatuses having a fixed emitting direction while the installation and usage environments are ignored, but these apparatuses cannot generate an optimal pattern to achieve an object of prompt reading.
On the other hand, the actual prompt reading depends, in addition to the scanning pattern, upon a moving path of merchandise (or barcode) by an operator. Even in a barcode scanner in which the scanning pattern is fixed to the optimal pattern for the installation and usage environments, a moving path slightly different among operators depending upon their heights, experiences, skillful hands, habits, etc. Disadvantageously, each operator must adjust a barcode moving path and spend a long time to master the operating skill.
To eliminate these problems, applicant has proposed, in Japanese Laid-Open Patent Application No. 9-16705, a barcode reader that generates a plurality of scanning patterns by making mirrors movable in the optical system, extending a scan area, and selecting one frequently used scanning pattern from them. Nevertheless, this invention was disadvantageous because it has a low reading reliance and does not always meet operative safety requirements.
The scanning pattern frequently used in this reference is not the actual optimal scanning pattern that has a high barcode-reading reliability. The optimal scanning pattern is one determined as a result of simulation taking into account the arrangement between a laser source and a light receiving element, while minimizing optical noises caused by mirror angles and the light amount of the laser beam. A scanning pattern including optical noises, even though hitting a barcode, cannot properly read the barcode data. For instance, a certain mirror angle puts the reflected light over the store""s light as a noise, and the light receiving element receives a large amount of incident light. A laser beam reflected at an edge or the like of the reflection mirror also causes a large amount of light incident to the light receiving element. In this way, a plurality of scanning patterns which have been generated only by taking into account the usage environment without paying attention to the optical noises would lower the reading reliance and delay the reading time. It is preferable to maintain the optimal scanning pattern that is set at the time of manufacturing.
In addition, as seen in the International Standard IEC and the U.S. Standard CDRH, which take care of human eyes subject to a laser beam, the laser safety standards define certain restrictions regarding the light amount of an incident laser beam. However, the light amount of an arbitrarily changed scanning pattern would not necessarily meet the above standards, thereby endangering safety.
Accordingly, it is a general object of the present invention to provide a novel and useful optical reader in which the above disadvantages are eliminated.
More specifically, it is another object to provide an optical reader which enables uniform manufacturing irrespective of the installation and usage environments.
It is still another object of the present invention to provide an optical reader that is user-friendlier than the conventional ones.
It is another object of the present invention to provide an optical reader which maintains the optimal scanning pattern and has a high reading reliance.
It is still another object of the present invention to provide an optical reader that meets the laser safety standards and secures safety.
In order to achieve the above objects, an optical device of the present invention comprises an optical unit which generates a predetermined scanning pattern, emits the predetermined scanning pattern to an optically readable medium, and receives light reflected from the medium, a stage which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit, and an inclination apparatus which inclines the stage.
Another optical device of the present invention comprises an optical device which includes a housing having a plurality of reading windows, a plurality of optical units accommodated in said housing, the number of the optical units corresponding to the number of reading windows, each optical unit generating a predetermined scanning pattern, emitting the predetermined scanning pattern to an optically readable medium, and receiving light reflected from the medium, a stage, accommodated in the housing, which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit, and an inclination apparatus, accommodated in the housing, which inclines the stage.
Still another optical device of the present invention comprises an optical unit which generates a predetermined scanning pattern, emits the predetermined scanning pattern to an optically readable medium, and receives light reflected from the medium, a stage which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit, an inclination apparatus which inclines the stage, and a controller connected to the inclination apparatus, the controller controlling the inclination of the stage by the inclination apparatus.
A scanning method of the present invention comprises the steps of generating a predetermined scanning pattern to read out an optically readable medium, changing an emitting direction of the predetermined scanning pattern to a desired direction while maintaining the predetermined pattern, emitting the predetermined scanning pattern to the desired direction, and reading out light reflected from the medium based on the predetermined pattern.
An optical device of the present invention comprises an optical unit which generates a predetermined scanning pattern, emits the predetermined scanning pattern to an optically readable medium, and receives light reflected from the medium, and an inclinable stage which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit.
Thus, the optical readers and scanning method of the present invention may change a scanning-pattern emitting direction while maintaining the predetermined scanning pattern.
Other objects and further features of the present invention will become readily apparent from the following description and accompanying drawings.